Some causes of fatigue and joint pain are chronic fatigue syndrome and rheumatoid arthritis, according to Mayo Clinic. Lupus is another condition that causes fatigue and joint pain, according to WebMD.
Medical experts do not know what causes chronic fatigue syndrome, according to Mayo Clinic. Other symptoms of condition include muscle pain, enlarged lymph nodes and trouble with concentration and memory.
Rheumatoid arthritis is an autoimmune disease that causes swollen, tender joints, states Mayo Clinic. Patients can also experience fever and weight loss. Lupus is also an autoimmune disease, states WebMD. Lupus causes the body's immune system to attack various organ systems.